Nitrogen and Irrigation on Coastal Plains Soils

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Nitrogen and Irrigation on Coastal Plains Soils

So why is it important to look at nitrogen in soils? First of all, it is a key element in organic molecules, so it is key to plant growth (Singer and Munns). Nitrogen is useful to plants in the form of nitrate because plants can take in nitrate and form organic molecules (Singer and Munns, 193). However, in soils, nitrogen in the form of nitrate (NO3) is considered a "mobile nutrient" which means that it can move easily through the soil to supply the needs of a plant (Singer and Munns, 221). That means it is accessible to the roots of plants, however, it also means that nitrate can be transported through a soil by moving with the water. This means that in sandy, or well-drained soils, nitrogen could be easily leached from the soil because nitrate is an anion that "moves freely with percolating water" and "water moves rapidly through sandy soils" (Hubbard, et. al., 802) So, when farmers add nitrogen to their soils, the nitrogen often stays in the soil for a limited amount of time before it is carried away by the water in the soil.

We should be concerned about the leaching of nitrogen from soils for several reasons. One problem is that as nitrogen is leached from the soils, it collects in the ground water and in surface streams. This can cause eutrophication, an excess growth of plants and algae, in nearby streams and lakes (Weil, et al, 441). Also, concentrations of nitrate of 10 mg/L or more in drinking water can cause methemoglobinemia, or blue baby syndrome in infants (Hubbard, 802).

In well-drained soils, organic material, which, of course, contains nitrogen, "may decompose faster than it is replenished (Dolman and Bud, 1967)" (Gambrell, et al, 321). So, in order to s...

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....; "Nitrate transport on a sandy coastal plain soil underlain by plinthite." Transactions of the ASAE, vol. 34(3), May-June 1989, p. 802-808.

Ritter, W.F., member, ASCE; Scarborough, R.W.; Chirnside, A.E.M.; "Nitrate leaching under irrigation on coastal plain soil." Journal of irrigation and drainage engineering, vol. 117 (4), 1991, p.490-502.

Ritter, W.F., A.E.M. Chirnside; R.W. Scarborough, Member, ASCE; "Soil nitrate profiles under irrigation on coastal plain soils." Journal of irrigation and drainage engineering, vol. 116 (6), 1991, p.738-751.

Singer, M.J., and Munns, D.N., 1996, Soils: An Introduction: Upper Saddle River, New Jersey, Prentice-Hall, Inc., 480p.

Weil, R.R.; Weismiller, R.A.; Turner, R.S.; "Nitrate contamination of groundwater under irrigated coastal plain soils." Journal of Environmental Quality, vol. 19, July - Sept. 1990, p.441-447.
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